- Modeling for 3D Printing
- Holes and Gaps
- General Best Practices
- Geometry Integration
- CAD Applications
- STL: Triangles, file size and 3d printing.
Tutorial: Convert a Google SketchUp file to a solid, 3D printable STL with the CADspan toolset
Here we will take a step-by-step look at using the CADspan SketchUp plugin to generate a solid, 3D printable STL file from a SketchUp model.
2. Isolate the geometry that you want to print, and use the CADspan style to visualize it for 3D printing. In this case, we just want to print the house, so I will turn off the layer containing the terrain. I will then click the CADspan style button
to render the model in a way that will make it easy to see if there are any holes or gaps in the model.
On first glance, the model seems pretty solid. However, when we look at the back of the house, I can see that there are some issues.
3. Fix the model. In this case, the rear wall needed to be pulled up to meet the bottom of the roof. Also, the small window's frame does not quite meet the wall above it. Both of these issues can be fixed with simple push-pull operations. The last issue was that the bottom of the roof plane was reversed. This was easily remedied by right-clicking on the face and selecting 'reverse faces.'
4. Convert to STL. Now the model looks solid all the way around. The windows are all closed with no gaps around them, same for the doors. All of the walls meet the roof under the eves and gables. There are no other noticeable holes or gaps. It's time to start converting to STL with CADspan. Click the CADspan button in the CADspan tool bar to bring up the CADspan Web Application in SketchUp's web browser.
Use this interface to resurface your model. Follow the built-in help '?' icons and instruction under the 'Help' tab to get a resurfaced version of your SketchUp model in the STL format. While CADspan's resurfaced output will always be "solid" and have no inverted triangles, it is HIGHLY RECOMMENDED that you use some sort of STL previewing software to check the accuracy of the output. Sometimes it will be necessary to adjust the settings and re-process your model to fine-tune the output. DO NOT print an STL file from CADspan without previewing it first. You can import the STL back into SketchUp if it is not very large, or use a mesh viewer like 3DCT's.
More on using CADspan
If you're wondering why you can't simply use an STL exporter to get a printable STL, try it for yourself. In SketchUp, Click the STL export button in the CADspan tool bar, and choose a destination for the STL file. This will dump all of the geometry into an STL file.
Now, to see what that file looks like to a 3D printer, click the STL import button in the CADspan toolbar. Navigate to the STL file you just exported.
Here are a "before and after" set of images showing what the STL looks like after being exported from SketchUp.
As you can see, there are some issues with faces being oriented the correct way. This is the nature of SketchUp geometry, even if you get the faces oriented the correctly in the SketchUp model, they will not necessarily be oriented the correct way in the STL export. This model would not print successfully; there would be voids in the windows where the glass panes' direction is reversed. For this reason, it is recommended to use the CADspan resurfacer as explained in step 4 above to create a new, solid mesh, with all faces pointed outward.